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 \begin{table}[htpb!]
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\caption{\textbf{Effect of maternal health on twinning (conditional      results)} \footnotesize{ Results from OLS regressions of a child's birth type (twin or singleton) on the mother's health behaviours and conditions are displayed.  Specifications are identical to those in table 1 in the    paper, however now all independent variable are included together.         Asterisks indicate significance levels of p-values, with: *p$<$0.1         **p$<$0.05  ***p$<$0.01. 95\% confidence intervals are displayed in        parentheses. Further details regarding estimation samples and variable     construction are available in Methods.}}
\scalebox{0.90}{\begin{tabular}{llcllc}
 \toprule\multicolumn{3}{c}{Health Behaviours / Access} &\multicolumn{3}{c}{Health Conditions } \\ 
\cmidrule(r){1-3} \cmidrule(r){4-6} 
Variable & Estimate & [95\% CI] &Variable & Estimate & [95\% CI]\\ \midrule 
\rowcolor{LightCyan} \multicolumn{6}{c}{\textbf{Panel A: United States}} \\ 
Smoked Before Pregnancy&0.225$^{***}$&[0.174,0.276]&Height&0.560$^{***}$&[0.533,0.587]\\
Smoked Trimester 1&-0.070$^{*}$&[-0.144,0.004]&Underweight&-0.180$^{***}$&[-0.205,-0.155]\\
Smoked Trimester 2&-0.176$^{***}$&[-0.276,-0.076]&Obese&0.102$^{***}$&[0.073,0.131]\\
Smoked Trimester 3&-0.171$^{***}$&[-0.259,-0.083]&Diabetes&-0.263$^{***}$&[-0.292,-0.234]\\
Education&0.678$^{***}$&[0.645,0.711]&Hypertension&-0.205$^{***}$&[-0.238,-0.172]\\
\rowcolor{LightCyan} \multicolumn{6}{c}{\textbf{Panel B: Sweden}} \\ 
Smoked (12 weeks)&0.049$^{*}$&[-0.008,0.106]&Height&0.612$^{***}$&[0.587,0.637]\\
Smoked (30-32 weeks)&-0.307$^{***}$&[-0.352,-0.262]&Underweight&-0.148$^{***}$&[-0.181,-0.115]\\
&&&Obese&-0.082$^{***}$&[-0.106,-0.058]\\
&&&Asthma&-0.005&[-0.023,0.013]\\
&&&Diabetes&-0.243$^{***}$&[-0.268,-0.218]\\
&&&Kidney Disease&-0.066$^{***}$&[-0.088,-0.044]\\
&&&Hypertension&-0.082$^{***}$&[-0.104,-0.060]\\
\rowcolor{LightCyan} \multicolumn{6}{c}{\textbf{Panel C: United Kingdom (Avon)}} \\ 
Healthy Foods&0.537$^{***}$&[0.253,0.821]&Height&0.408$^{***}$&[0.122,0.694]\\
Fresh Fruit&-0.116&[-0.422,0.190]&Underweight&-0.191&[-0.469,0.087]\\
Alcohol (Infrequently)&0.069&[-0.251,0.389]&Obese&-0.008&[-0.286,0.270]\\
Alcohol (Frequently)&-0.398$^{**}$&[-0.716,-0.080]&Diabetes&-0.065&[-0.337,0.207]\\
Passive Smoke&0.193&[-0.121,0.507]&Hypertension&-0.479$^{***}$&[-0.751,-0.207]\\
Smoked during Pregnancy&-0.165&[-0.475,0.145]&&&\\
Education&0.384$^{*}$&[-0.039,0.807]&&&\\
\rowcolor{LightCyan} \multicolumn{6}{c}{\textbf{Panel D: Chile}} \\ 
Smoked during Pregnancy&-0.254$^{**}$&[-0.493,-0.015]&Underweight&-0.186$^{*}$&[-0.396,0.024]\\
Drugs (Infrequently)&0.015&[-0.234,0.264]&Obese&-0.265$^{***}$&[-0.439,-0.091]\\
Drugs (Frequently)&-0.095$^{***}$&[-0.138,-0.052]&&&\\
Alcohol (Infrequently)&-0.066&[-0.348,0.216]&&&\\
Alcohol (Frequently)&-0.114$^{***}$&[-0.159,-0.069]&&&\\
Education&0.420$^{***}$&[0.100,0.740]&&&\\
\rowcolor{LightCyan} \multicolumn{6}{c}{\textbf{Panel D: Developing Countries}} \\ 
Doctor Availability&0.036&[-0.009,0.081]&Height&0.269$^{***}$&[0.238,0.300]\\
Nurse Availability&0.045$^{**}$&[0.006,0.084]&Underweight&-0.085$^{***}$&[-0.110,-0.060]\\
Prenatal Care Availability&0.042$^{**}$&[0.003,0.081]&Obese&0.046$^{***}$&[0.015,0.077]\\
Education&0.083$^{***}$&[0.050,0.116]&&&\\
\bottomrule 
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